Thread-cutting device.



J. J. SULLIVAN.

THEE-AD CUTTING DEVICE.

APPLICATION FILED 001.5, 1911.

1,066,862, Patented July 8, 1913.

W/TNESSES; mvmron %z% y g 5% 7441/2 TERM , 2g viding one of the independently sustained UNITED STATES PATENT OFFICE.

JOHN J. SULLIVAN, or rrswrcn, MASSACHUSETTS, lassmnon To THE SINGER MANIL' rAcTUnING COMPANY, A CORPORATION or NEW JERSEY.

THREAD-CUTTING DEVICE.

Specification of Letters Patent.

Patented July 8, 1913.

Application filed October 5,1911. Serial No. 652,934.

of Massachusetts, have invented certain new and useful Improvements in ThreadCutting Devices, of which the following is a specification, reference being had therein to the accompanying drawings.

This invention relates more particularly to an improvement in that class of rotary -work-clamps for buttonhole sewing machines forl'fling the subject of the United States patent to J. G. Greene No. 319,700, of June 9, 1885, and .it has for its object to provide a simple and effective thread-severing and holding device adapted to be operated at the completion of a buttonhole stitching operation to sever the needle-thread and hold the cut end thereof leading to the needle in readiness for beginning the succeeding stitching operation.

The. invention consistsessentially in profeet of the upper .work-clamping member with relatively fixed and spaced thread-nipping and severing jaws at its inner edge and I in interposing between suchjawsa transversely reciprocating slideplate having thread-nipping and severing shoulders mbvable into and out of operative relation with the fixed jaws, means being provided for reciprocating said slideplates to engage the needle-thread extending from the final stitch of a buttonhole to the eye of the needle and for drawing the same between said jaws whereby the thread is'nipped between the upper face of the slide-plate and the fixed nipping jaw and is thereafter severed between thelower face of the slide-plate and the fixed severing aw whose operatlveedge is arranged slight y rearward of the nipping jaw. The slide-plate preferably has a loose connection with a spring operating lever fulcrumed upon the lower clamp member independently of the pivotal connection of the upper clamp member therewith but adapted to follow the closing and opening movements of the upper clamp member for clamping and releasing the work.

The invention will be understood by referenbe to the accompanying. drawings, in

which.- I Figure 1 is a perspectrve view of a button; hole clamp provided with "the present m .wardly are secured the provement, and Fig. 2 an enlarged sectional "plan view of the part thereof provided with the nipping and cutting devices. Fig. 3 is a front end elevation of the clamping footprovided with the nipping and cutting members, and showing its method of'operation in connection with a stitched buttonhole, and

Fig. 4 is a perspective view ofth'e cutterplate detached.

The worklamp herein shown is of the type commonly employed in the wellknown;

Singer rotary-clamp buttonhole machine, constructed substantially as represented inthe United States patents to J, ,G. Greene Nos. 360,433, 360,434 and 360,435fdated April 5, 1887. It is constructed with a base plate 1 formed with the needle aperture or 'slot 2 whose walls embrace the needle-throat or button of the machine by which the clamp guided in its travel in conjunction wit the usual depending guidein (not shown).

The base-plate 1 1s provi 3 to which are fitted the reduced extremities of the laterally movable clamp-plates 4 af fording the lower work-clamping jaws, the

a with the gibs plates '4 being provided at the rearward e'nds with the fulcrum-blocks 5 formed with rear extending ears 6 receiving the fill 7 for the tilting blocks 8' to which independently movable spring arms 9 of the upper clamp member to whose outer ends are pivotally connected by means of the pins 10 the clam in feet'll and 12;" Intermediate their end; t e upper clamp arms 9 are embraced by .the slotted cross-bar 13 of a link 14 whose lower end embraces a -crank 15 of a transverse shaft 16 fulcrumed in the fulcrum-blocks 5 and procrum-pins vided with the finger-lever 17 for operating the. same to clamp and unclalnp the work.

The adjacent edges of the. clamping feet 11 and 12 are recessed in the usual manner to afford an intermediate needle apertureto .expose the face of the work receiving the oversea-m stitches of the butto'nhole.

, The clamping foot 12 is provided in its inner edge with a longitudinal slot 18 substantially parallel with its operative face so as to form above the same a rigid threadnipping jaw 19 whose operative edge is dis posed in substantial alinement 'with the adjacent edge of the foot 12, and a rigid lower jaw spaced therefrom and beveled in itsouter portion to form a sharp edge at its intersection-with the lower face of the foot and to afford an obtuse-angled thread-severing shoulder 20 disposed somewhat beyond the operative edge of thenipping-jaw, as represented in Fig. 3.

The foot 12 has in register with the slot 18 and also disposed substantially parallel with the operative face thereof atransverse slideway 21 to which is fitted the sliding cutter plate 22 formed with a laterally pr jecting head 23 presentingat'its upper and lower faces in opposition to the fixed nip ping and severing shoulders 19 and 20 the cooperating movable shoulders 24 and 25. The operative end portion of the slide-plate 22 is preferably formed with a slit 26 parallel with its upper andlower faces to adapt the shoulders 24' and 25 to yield slightly in their engagement with the needle thread to prevent the crushing of the thread interposed between the shoulders19 and 24. The nipping and severing shoulders 19 and 20 are so designated to indicatetheir respective functions in conjunction with the shoulders 2i and 25 oft-he slide-plat'e22 which, in practice, have the usual respectively blunt and sharp edges; the elements 20 and 25 being designed to cooperate in the severing operation to successively pinch and tearthe thread which is firmly connected on opposite sides thereof by the nipping elements lil and 24 on the one hand and the work still gripped'by the clamp on the other. In case the thread should'not actually be severed by such means, the lateral shifting of the work after opening the fclamp will bring -the, thread into contact with the sharp edge of the jaw/20 by means of which the still taut.

thread will be cut off'close to the work.

The slide-plate 22 has swiveled in its rearward end the eye 27 which embraces the operating-lever 28. which is shown with its outer end bent into an eye 29, with a portion near its oppositeend flattened and bentinto a Ueshaped spring 30 and having at its extremity thefulcrum-pin 31 disposed transversely to the body portion and fitted within a correspondingly arranged bearing aperture 32in the fulcrum-block 5 beneath and parallel with the clamp-arm actuating rockshajft 16; The operating lever, constructed and arranged as described. is enabled to swing vertically to follow the opening and closing movements of the upper clamp member and to yield laterally from initial outer position (represented in dotted lines in Fig. 1) to inner thread-engaging position substantiallv as represented in full lines in said figure. the swiveled eve 27 affording a loose connection between the same and the slideplate 22 compensating for changes in angular relation of the parts thus connected in the operation of the nipping and severing device.

In the operation of the device, the mate-- lower clamping members and the clamp closcdthereon, after which the machine is set in motion and the series of covering stitches s is applied in the usual manner, the

'wcrk-clamp being-given a semi-rotation in stitching the eye of the buttonhole. At the completion of the stitching operation, and

after the machine comes to rest, the needlethread leads upwardly from the last stitch to the eyeinf the needle n, as represented in Fig. 1.. Before the position of the clamp is disturbed, and while-the material is still held therein, the lever 28v is drawn-inwardly by the operator toim'ove the head of the slide-plate 22inwardly partially across the needle aperture so as to bring itsshoulders 24 and 25 beyond the taut needle-thread, the roundedportion 23? of the head serving to thrust aside the needle-thread which snaps in behind its operative shoulders, as reprey ries the needle-thread intooperative engagement with the fixed shoulder 19 to' nip the same, after which the continued receding movement progressively draws in the portion of the thread between such point and the work to firmlyclampthe same until the portion of thread thus tightened is brought into engagement with the severing shoulder 20' by which it is parted close to the work so as to leave a very short end attached thereto,

ice

the loose end leading to the needle being held nipped while the clamp is turned into initial position and opened for replacement or shifting of the materialfor a'succeeding operation, the thread end being still held. in

this nipper after the closihg of theclamp to insure the proper formation of the initial stitch of'a succeeding buttonhole.

From the foregoing description, it will be seen that the present improvement is not limited to the precise constructive features herein shown and describednor to application to the particular form of work-clamp above referred to. it being-adapted for employment with other formsof work-holding members, as for instance the presser-foot of a straight-away sewing machine, the thread engaging parts and their operating means being designed accordingly.

Having thus set forth the nature of the invention, what I claim herein is:

1. A work-clamp comprising a clamping foot having at one edge spaced jaws mteri mediate which and disposed substantially parallel with the operative face of the fqot is a guideway. a slide-plate fitted to said guideway and having a lateral extension affording thread-nipping and severing shoul 3 ders. acting in conjunction with said jaws, an operating lever fulcrumed upon said clamp, and a pivotal connection between said lever and slide-plate.

2. The combination with a work-clamp constructed with a lower clamping member and an upper clamping member pivotally connected therewith and provided with a needle-aperture and with a guid'eway connected with said aperture to form at the intersection therewith spaced thread-nipping and -severing jaws, a reciprocating cutterplate fitted tothe guideway and provided with thread-engaging shoulders acting in conjunction with said spaced jaws and movable into the needle-aperture, an operating lever fulcrumed upon said clamp, and a pivotal connection between said lever and cutter-plate.

3. The combination with a work-clamp constructed with separable upper and lower clamping members the former of which is provided with a needle-aperture, of spaced thread-nipping and severing jaws carried by the. upper clamping member and a sharp cutting edge below the severing aw at substantially the level of the work-engaging face of said member, a reciprocating cutter-plate provided with thread-engaging shoulders acting in conjunction with and movable between said spaced jaws and into the needle-aperture, and means sustained by said clamp for actuating said cutter-plate.

4. The combination with a work-clamp constructed with a lower clamping member and an upper clamping member pivotally connected. therewith and provided with a needle aperture, of spaced thread-nipping and -severing jaws carried by the upper clamping member, a reciprocating cutterclamping member independently of the upper clamping member, and an operative connection between said lever and the cutterplate.

5. The combination with a work-clamp constructed with a lower clamping member provided with a fulcrum-block and an upper clamping member pivotally mounted upon said fulcrum-block and provided with a needle aperture, of spaced thread-nipping and -severing jaws carried by the upper clamping member at one side of said aperture, a reciprocating cutter-plate slidingly fitted within the upper clamping member and provided with thread-engaging shoulders acting in conjunction with and movable between said spaced jaws and into the needle aperture, and an operating lever operatively connected with said cutter-plate and formed with a transversely extending fulcrum-pin journaled in the fulcrum-block of said lower clamping member and having intermediate said fulcram-pin and its connection with the cutter-plate a resilient portion adapted to maintain the lever yieldingly in an initial position.

In testimony whereof, I have signed my name to this specification, in the presence of two subscribing witnesses.

' JOHN J. SULLIVAN.

Vitnesses:

D. P. BIRNIE, H. J. MiLLER.v 

